Author/Authors :
Shahmir، M. نويسنده Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran , , NILI AHMADABADI، M. نويسنده , , Naghdi، F. نويسنده Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran ,
Abstract :
In the present study the effect of thermomechanical treatment (cold work and annealing) on the
transformation behavior of NiTi shape memory alloys was studied. Differential scanning calorimetry was used to
determine transformation temperature and its relation to precipitates and defects. Three alloys including Ti-50.3at.%
Ni, Ti-50.5at.% Ni (reclamated orthodontic wires) and 50.6at.% Ni alloy were annealed at 673 K and 773 K for 30
and 60 min after 15% cold rolling. It was found that the transformation characteristics of these alloys are sensitive to
annealing treatment and composition. The temperature range of transformation is broadened during cold working and
after subsequent annealing, the intermediate phase was appeared. The peaks become sharper and close together on
each cooling and heating cycle with increasing annealing temperature and time
